The results for diffraction limit is variable depending on whether you use points or lines and a figure of 1/100 for f/22 isn't impossible. Likewise, the MTF of the film is very difficult to read 'accurately' as it depends on contrast.

Developer will make a difference also and getting absolute accuracy is difficult. However, you should read that at the bottom they say that the survey is intended as a 'relative' comparison of the lenses on test..